Bruno, the first point is that it isn't correct that a basic receiver with just HDMI "switching" would do what you want. Those receivers just combine two or more HDMI inputs and allow one to be selected for the HDMI cable for the video to the TV. They don't have processing for audio through HDMI and a separate cable for audio(not carrying the new audio formats)would be necessary.
If you want to change your receiver because of HDMI, either the Onkyo 606 or Yamaha 663 should meet your needs. From research on another recent question I'm aware that the 606 doesn't change the video signal that is input on HDMI(e.g., 720p in, 720p out).
